Such receptacles are commonly known and widely used for holding and/or storing substances such as fluids or liquids of all kinds, but particularly foodstuffs, cosmetics or body care products.
DE 34 18 597 A1 describes a bag of the above-mentioned kind and comprising a valve that has two valve flaps forming pouches between the outside sheets and the valve flaps. The valve flaps are attached by transverse welds to the respective insides of their channel. The pouches are open in the direction of the interior of the bag. The outside sheets and the valve flaps are welded to each other along two longitudinal welds so that a narrow tubular inner inlet and inner pouches are formed on each side of the inner inlet in the lower region of the inlet. The inner pouches remain expanded due to the entry of air from the flat bag, so that when liquid flows back it can enter the inner pouches and, from there, over the inner tubular inlet, thereby squeezing together and sealing the inlet. In other words, liquid cannot exit the bag once it is filled into the interior of the bag.
In very many situations, however, a user would at some point desire to retrieve the liquid contained in the receptacle such as to use the liquid in an intended manner. A wide variety of uses is of course feasible depending on the type and nature of the liquid. In such situations the bag according to DE 34 18 597 A1 is disadvantageous in that retrieval of the liquid contained in the bag is not possible unless the bag is torn open, in which case the risk of spilling the liquid is very high.
An attempt at a solution is described in EP 1 162 152 A1 which concerns a bag container with a cylindrical, rigid check valve attached to the bag container by means of a combination of heat shrinking and gluing. This valve solution is however expensive to manufacture due to both the complicated structure of the check valve and the complicated procedure to be used to attach the valve to the bag container. Furthermore, due to the check valve, such a bag container takes up much space during storage and transport, especially when it is empty and is heavy. Also, due to the position of the check valve, such a bag container requires a separate lid to prevent spilling and particularly to keep the valve sanitary during transport and storage of the container.